Drainage control device for papermaking machine



June 6, 1967 R. c, HEYS 3,323,981

DRAINAGE CONTROL DEVICE FOR PAPER-MAKING MACHINE Filed Sept. 2, 1964 3 Sheets-Sheet 1 W C. gqventor mflilfv W A ttorneys' June 6, 1967 R. c. HEYS 3,323,981

' DRAINAGE CONTROL DEVICE FOR PAPERMAKING MACHINE Filed Sept. 2, 1964 I 3 heets-Sheet Inventor A tlorne y 5 June 6, 1967 R. c. HEYS DRAINAGE CONTROL DEVICE FOR PAPER-MAKING MACHINE 5 Sheets-Sheet Filed Sept.

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United States Patent 3 323,981 DRAINAGE CONTROL DEVICE FOR PAPER. MAKING MACHINE Ralph C. Heys, Sheflield, England, assignor to Millspaugh Limited Filed Sept. 2, 1964, Ser. No. 393,986 Claims priority, application Great Britain, Sept. 6, 1963, 35,229/ 63 4 Claims. (Cl. 162-352) This invention relates to paper-making machines of the Fourdrinier type, and is directed to the removal from the forming wire of such a machine of water drained from the layer of stock carried by the wire.

Although much of the very high content of water in the stock drains progressively through the wire in the passage of the latter from the forming end to the couch end, a significant amount of the water remains entrained on the undersideof the wire and, with air also drawn along by the movement of the wire, interferes with the free drainage of water. When this entrained water reaches the table rolls used to support the wire it is forced into the ingoing nip between the wire and each roll and thence upwardly to exert a disruptive effect on the paper mat being formed. This tendency is augmented by the flow of air induced by the wire movement. Moreover, water may be sprayed from one table roll onto the next roll and add to the entrained water that is being similarly carried into the ingoing' nip between the wire and that next roll.

The object of the invention is to effect removal of water entrained on the underside of the wire, and to utilise in that removal the air and water carried along by the wire itself.

According to the present invention, a doctor for application to the underside of the forming wire of a Fourdrinier paper-making machine, the doctor being provided with a rearward lip to make contact transversely of the wire and having forwardly of an extension the lip with an upper surface co-extensive with the length of the lip transverse to the wire and sloping downwardly away from the lip, there being holes piercing the extension from its upper surface.

Water on the underside of a Wire to which the doctor is applied, with the lip in contact with the wire, is carried together with air into the space between the extension and the wire. That space converging towards the lip, there is a tendency to progressive increase of pressure of the water in the space, and this promotes a flow of water (and air) through the holes progressively encountered in the extension, so that water is forced away from the wire, to pass to the underside of the extension. The succession of outlets provided by the holes for the water avoids any sudden build-up of pressure immediately in advance of the lip of the doctor; instead, therefore, of a disruptive effect at the lip, the pressure of the water is not only eased by the escape of water through the holes but is applied to the paper mat over an area having a width (in the direction of the wire) equal to the forward dimension of the extension.

Preferably, the doctor is mounted for adjustment about a transverse axis, so that the inclination of the surface of the extension can be varied. Thus, the doctor may be mounted on a transverse shaft, and the upper surface of the forward extension may be concentric with the axis of the shaft.

The doctor may be formed with an enclosed chamber below the lip and its extension, for the collection of water carried through the holes, the chamber having one or more discharge outlets. Such outlet or outlets may be provided by a tube used as the doctor shaft, the tube wall 3,323,981 Patented June 6, 1957 being apertured, e.g., slotted or perforated, within the chamber, for the extraction of water through the tube. To assist the drawing of the water through the holes in the extension, and to remove water from the chamber, vacuum or high velocity air may be applied to the outlet or outlets.

A mounting with provision for height adjustment of the doctor enables the lip to make any desired contact with the Wire, and also allows compensation for wear of the lip.

The lip is preferably formed of fabricor fibre-reinforced plastics material, and may be formed integrally with an extension of such material.

The forward end of the extension may be provided with a lip, over which the entrained water must first pass, then to be free to move downwardly towards the holes in the extension. By the angular adjustment of the doctor, this lip may, if required, be brought into contact with the underside of the wire, to strip off water, and thus to leave the extension to deal with water drained through the wire over the extension itself.

A rolling support for the wire doctor rearwardly of its rear lip, so that the weight of the wire is not taken solely by the lip. Thus, the doctor may be provided with two rows of staggered rollers of small diameter.

A plurality of the doctors may be disposed in succession along the wire, whether or not the wire is also supported by table rolls. By the provision of supporting rolls on the doctors, the table rolls may be dispensed with. The doctors may even render unnecessary the use of vac uum boxes under the length of the wire immediately in advance of the couch roll.

Again, the doctors may be used in association with table rolls. Thus a doctor may be mounted on the machine frame in advance of a table roll, with lengthwise adjustment to permit it to be accurately located with respect to that roll. Yet again, one or more of the doctors may be included in a table roll assembly.

The invention will now be further described with refermay be carried by the ence to the accompanying drawings, in which:

FIGURE 1 is a side elevation of two doctors, each incorporating an enclosed chamber, alternating with three table rolls;

FIGURE 2 is a longitudinal section of one of the doctors and one of its mountings, taken on the line IIII of FIGURE 1;

FIGURE 3 is a cross-section of a doctor, incorporating enclosed chamber, provided with two modifications;

FIGURE 4 is a side elevation of a table roll assembly having one internal doctor and two external doctors;

FIGURE 5 is a plan of FIGURE 4;

FIGURE 6 is a section through the internal doctor of FIGURE 4, taken on the line VIVI; and

FIGURE 7 is a section through one table roll of FIG- URE 4, taken on the line VII-VII.

In FIGURE 1, table rolls 1, 2, 3 extend transversely below a forming wire 4, they being supported from the side frames 5 of the machine by bearing brackets 6 (shown only in respect of the roll 2). Brackets 7 carried by the side frame 5 each include two vertical plates 8 with guide pads 9 on each to receive a bearing block 10, adjustable for height by a screw 11. A tubular shaft 12 is rotatable supported at each end by one of the hearing blocks 10 and is rotatably adjusted by a screw 13 pivoted to a lever arm 14 welded to the shaft.

A chamber 15 is secured to the shaft 12, the chamber having walls 16, 17 welded along the shaft and end plates 18 (one only shown in FIGURE 2), a doctor board 19 of thick fibre-reinforced plastics material being secured over the mouth of the chamber. The chamber 19 is upstanding from the shaft 12, its normal position of use being with the rear plate 17 upright, so that the rear portion of the doctor board forms a lip 20 to contact the underside of the wire 4.

From the rear lip 20, the upper surface 21 (FIGURE 1) of the doctor board 19 diverges downwardly from the wire 4, the surface 21 being concentric with the shaft 12. Rows of holes 22 (see also FIGURE pierce the doctor board 19 from the surface so that the water entrained on the underside of the wire is carried into the chamber 15, together with air carried along with the water. The wire 4 moves from left to right as seen in FIGURE 1, and the convergence of the space between it and the surface 21 in the direction of the rear lip 20 assists in urging the water through the holes 22.

Apertures 23 in the top of the tubular shaft 12 allow the water carried into the chamber to enter the shaft, for removal from the end 24 of the shaft beyond the block 10, either by free drainage or by the application of vacuum to the shaft by a suction pump or a flow of high velocity air induced by a fan. The resultant depression of pressure within the chamber 15 assists the flow of water and air through the holes 22.

The height adjustment afforded by the screw 11 in each bracket 7 enables the height of the surface 21 of the doctor board to be adjusted with respect to the uppermost height of the table rolls 2, and the angular adjustment afforded by the screw 13 enables the wire 4 to meet the surface 21 at varying distances from the rear lip 20. As shown by FIGURE 3, the holes 22 may start from a depressed surface 21A, disposed between a front lip 25 and the rear lip 20, and the front lip 25 may be brought into closer approach to the underside of the wire 4 by use of the angular adjustment afforded by the screw 13 of FIGURE 1, even to the extent that the front lip 25 can make actual contact with the wire if circumstances demand, to throw off water down the front of the chamber 15.

The brackets 7 have bases 26 (FIGURE 2) movable lengthwise of the frames 5, to be locked by screws 27 when the entire doctor assembly has been adjusted relatively to the succeeding table roll 2. Therefore, together with the vertical and angular adjustment, the doctor board may be so adjusted relatively to the wire 4 and the succeeding table roll 2 that the rear lip 20 of the doctor maintains contact with the wire, at the rear of a wedge between the wire and the surface 21 (or 21A) into and along which the water and air immediately under the wire is forced to pass. However, to relieve the rear lip 20 from the total weight of the wire and the mat of fibre on the wire, rolling support may be provided immediately to the rear of the lip. As shown by FIGURE 3, this support may be provided by two rows of small diameter rollers 28 rotatable in brackets 29 mounted on the rear plate 17 of the chamber 15.

In FIGURES 4 to 7, two table rolls 2 form part of an assembly based on a chamber 30 the front and rear edges 31, 32 and side edges 33 of which are provided with strips of fabric-reinforced plastics material to make sealing contact with the underside of the wire 4. Each roll 2 is mounted in self-aligning bearings 34 (FIGURE 7) carried by brackets 35 mounted on the sides of the chamber 28. Further brackets 36 (FIGURE 6) carry blocks 10 for the tubular shaft 12 on which a doctor board 19 is mounted by end plates 18 welded to the shaft, with screws 11 and 13 for vertical and angular 4 adjustment. The doctor is as in FIGURE 3, viz, with with a depressed surface 21A between a front lip 25 and the rear lip 21.

Water and air passing through the holes 20 in the doctor may be extracted either by the tubular shaft 12, if the space below the doctor is enclosed, as in FIGURES 1 and 3, or it may be discharged into the chamber 30 of the whole assembly, to be extracted through an outlet 37, which is preferably connected to a suction pump or a high velocity air fan.

Fixed, but adjustable, doctor blades 38 (FIGURE 4) extend across the chamber 30 to contact the upwardly moving side of each table roll 2, to strip water from the surface of the roll before it can be returned to the underside of the wire 4.

Doctor boards 19 are mounted in brackets 39 outside the front and rear of the chamber 30. The brackets are adjustable in height by the screws 40. The doctor boards may also be adjustable angularly as previously described.

What I claim is:

1. A doctor for application to the underside of the forming wire of a Fourdrinier paper-making machine, together with a mounting to enable contact to be made across the width of the wire by the doctor, wherein the mounting includes a transverse pivotal connection to the doctor, and means for angularly adjusting the doctor about the axis of the said connection, and the doctor includes a board with an arcuate surface concentric with the said axis, the board being formed with a plurality of holes downwardly from its arcuate surface for the removal from the wire of water and air entrained by the underside thereof and carried by the movement of the wire into the space between the arcuate surface and the wire towards the transverse line of contact made between the wire and the part of the surface of the angularly adjusted board held in contact with the wire by the mountmg.

2. A doctor as in claim 1, wherein the doctor includes a vacuum chamber of which the board forms the top, and the transverse pivotal connection of the mounting serves also as a vacuum connection to the vacuum chamher.

3. A plurality of doctors as in claim 1 carried by their respective mountings in advance of the table rolls for supporting the wire of a Fourdrinier machine.

4. A plurality of doctors as in claim 1, an open-topped vacuum box, and a plurality of table rolls rotatably mounted in and transversely to the vacuum box, the mountings of the doctors being carried by the box so that the doctor boards extend transversely of the box, and at least one of the doctors and its mounting being carried inside the box in advance of a table roll within the box.

References Cited UNITED STATES PATENTS 2,170,109 8/1939 Berry l62352 3,017,930 1/1962 Dunlap 162-352 3,084,740 4/1963 Carrel 162-373 3,239,409 3/1966 Knowles 162352 FOREIGN PATENTS 399,739 10/1933 Great Britain.

DONALL H. SYLVESTER, Primary Examiner.

J. H. NEWSOME, Assistant Examiner, 

1. A DOCTOR FOR APPLICATION TO THE UNDERSIDE OF THE FORMING WIRE OF A FOURDRINIER PAPER-MAKING MACHINE, TOGETHER WITH A MOUNTING TO ENABLE CONTACT TO BE MADE ACROSS THE WIDTH OF THE WIRE BY THE DOCTOR, WHEREIN THE MOUNTING INCLUDES A TRANSVERSE PIVOTAL CONNECTION TO THE DOCTOR, AND MEANS FOR ANGULARLY ADJUSTING THE DOCTOR ABOUT THE AXIS OF THE SAID CONNECTION, AND THE DOCTOR INCLUDES A BOARD WITH AN ARCUATE SURFACE CONCENTRIC WITH THE SAID AXIS, THE BOARD BEING FORMED WITH A PLURALITY OF HOLES DOWNWARDLY FROM ITS ARCUATE SURFACE FOR THE REMOVAL FROM THE WIRE OF WATER AND AIR ENTRAINED BY THE UNDERSIDE THEREOF AND CARRIED BY THE MOVEMENT OF THE WIRE INTO THE SPACE BETWEEN THE ARCUATE SURFACE AND THE WIRE TOWARDS THE TRANSVERSE LINE OF CONTACT MADE BETWEEN THE WIRE AND THE PART OF THE SURFACE OF THE ANGULARLY ADJUSTED BOARD HELD IN CONTACT WITH THE WIRE BY THE MOUNTING. 